Lesson 1 #20

For this problem, there are multiple operations to be performed.  When there is more than one operation, you need to use the correct order of operations when you carry out the operations or else you may get an incorrect answer.

The order of operations is PEMDAS

Parentheses (Parentheses are not an operation.  They are an indicator to perform some other operation that is in parentheses first)

Exponents

Multiplication/Division (from left to right whichever comes first)

Addition/Subtraction (from left to right whichever comes first)

Sometimes it is useful to start by identifying how many and what type of operations you need to perform.  This will keep you from jumping in and performing the first operation you see.

Notice in the image above there are three operations to be performed: two additions and one multiplication.  Normally, multiplication would come first.  However, the parentheses around the addition portion 8 + 2 indicates that we do this addition first.  The result is shown below.

Now we have addition and multiplication.  Although there are parentheses around the number 10, there is not a remaining operation in the parentheses to perform. The parentheses in this case are just indicating multiplication between 8 and 10.   We can drop the parentheses, but we must replace it with a multiplication sign as shown above and to the right.  

Next we perform the multiplication and then finally the remaining addition as shown below.